The present invention relates to a toroidal printed coil manufacturing method as well as to a toroidal printed coil manufactured by the manufacturing method. The toroidal printed coil manufacturing method according to the present invention is suited for manufacturing a plurality of toroidal printed coils simultaneously, and a printed coil sheet to be used in the processes of the manufacturing method can also be used as a printed wiring board having a plurality of toroidal printed coils. Toroidal printed coils obtained by the present invention are used as inductance devices, antennas, solenoid coils, motor coils and the like.
A printed coil manufacturing method according to the prior art is described with reference to FIG. 8.
There has been known a coil manufacturing method comprising the following steps. That is, as shown in FIG. 8, long, narrow and linear through slits 11, at least two in number, are formed in an insulating substrate 10 so as to be opposite to one another with a specified spacing. Metal layers are formed at front and rear surfaces of the insulating substrate 10 as well as inner surfaces of the through slits 11. The metal layers of the front and rear surfaces of the insulating substrate 10 except portions 16 forming a plurality of coil wires are removed, and the insulating substrate 10 is cut at cutting lines A, B, C, and D along the through slits 11. Then, in the cutting sections, except connection-use metal layers for individually interconnecting the metal layers of coil-wire forming portions of the front and rear surfaces of the insulating substrate 10, the metal layers of the inner surfaces of the through slits are removed. Therefore, the metal layers of the front and rear surfaces of the insulating substrate 10 are connected spirally to one another, by which coils are manufactured (Japanese Laid-Open Patent Publication No. 59-103321).
However, this m method has a large number of manufacturing steps and is complex, due to the steps of forming metal layers forming a plurality of coil wires at the front and rear surfaces of the insulating substrate as well as the inner surfaces of the through slits, then cutting the insulating substrate along the through slits, and thereafter further connecting the metal layers of the front and rear surfaces of the insulating substrate to one another spirally.
Accordingly, an object of the present invention is to solve the aforementioned issues and to provide a toroidal printed coil manufacturing method which allows toroidal printed coils to be manufactured with great simplicity without requiring much time and labor, and to provide a toroidal printed coil manufactured by this manufacturing method.
In order to achieve the above object, the present invention has the following constitutions.
According to a first aspect of the present invention, there is provided a toroidal printed coil manufacturing method for simultaneously manufacturing a plurality of toroidal printed coils including a plurality of annular holes, a plurality of center holes, and annular juts formed on an insulating substrate. The annular juts are formed of a plurality of annular portions surrounded by the plurality of annular holes and the plurality of center holes surrounded by these annular holes. Each annular portion is taken as an axis, forming a conductor film at front-and-rear surfaces and inner-and-outer side surfaces of the annular portion simultaneously and spirally.
According to a second aspect of the present invention, there is provided the toroidal printed coil manufacturing method according to the first aspect, wherein the plurality of annular holes and the plurality of center holes surrounded by these annular holes are formed in the insulating substrate prior to forming the conductor film.
According to a third aspect of the present invention, there is provided the toroidal printed coil manufacturing method according to the first or second aspect, wherein for the formation of the conductor film, after a plating resist layer is formed and patterned at portions of the front-and-rear surfaces and the inner-and-outer side surfaces other than portions to be left as the conductor film, plating process is performed so that the conductor film is formed at the portions to be left as the conductor film.
According to a fourth aspect of the present invention, there is provided the toroidal printed coil manufacturing method according to the first or second aspect, wherein for the formation of the conductor film, after the conductor film is formed generally entirely at the front-and-rear surfaces and inner-and-outer side surfaces of the annular jut, unnecessary portions of the generally entirely formed conductor film are removed by irradiation of a laser beam or the like so that the conductor film is formed at only necessary portions.
According to a fifth aspect of the present invention, there is provided the toroidal printed coil manufacturing method according to the first or second aspect, wherein for the formation of the conductor film, after the conductor film is formed generally entirely at the front-and-rear surfaces and inner-and-outer side surfaces of the annular jut, an etching resist layer is formed and patterned at portions to be left as the conductor film, unnecessary portions of the generally entirely formed conductor film are removed by etching so that the conductor film is formed at only necessary portions.
According to a sixth aspect of the present invention, there is provided the toroidal printed coil manufacturing method according to any one of the first, second, and fifth aspects, further comprising preparing a copper-clad laminate in which a copper foil is cladded on front and rear surfaces of the insulating substrate. The center holes are formed through the insulating substrate and the annular holes are formed so that the annular portion of each annularjut has a specified width and so that a portion for connecting with the other portion of the insulating substrate is left, by which the plurality of annular juts are formed. Copper plating is generally formed entirely at the front-and-rear surfaces and inner-and-outer side surfaces of the annular portion of each annular jut. Etching resist is formed congruous with the spiral conductor film with the annular portion of the annular jut taken as an axis. Unnecessary portions of the generally entirely formed conductor film are then removed, by etching, where the etching resist has not been formed. The etching resist is thereafter flaked off from the insulating substrate, by which the conductor film is obtained.
According to a seventh aspect of the present invention, there is provided the toroidal printed coil manufacturing method according to any one of the first to sixth aspects, further comprising forming terminals of start and end portions of the spiral conductor film at the connecting portion and in the same plane by etching. Portions of the coil terminal portions other than copper-foil portions are coated, with solder resist, to thereby insulate those portions, and then the connecting portion is cut, by which the plurality of toroidal printed coils are obtained.
According to an eighth aspect of the present invention, there is provided the toroidal printed coil manufacturing method according to any one of the first to seventh aspects, wherein each of the center holes is circular shaped and a perimeter of the annular portion of the annular jut has a circular shape concentric with the center hole.
According to a ninth aspect of the present invention, there is provided the toroidal printed coil manufacturing method according to any one of the first to eighth aspects, wherein each of the center holes is polygonal-shaped and a perimeter of the annular portion of the annular jut has a polygonal shape similar to the center hole.
According to a tenth aspect of the present invention, there is provided the toroidal printed coil manufacturing method according to any one of the first to ninth aspects, wherein the conductor film is uniform in width.
According to an eleventh aspect of the present invention, there is provided the toroidal printed coil manufacturing method according to any one of the first to tenth aspects, wherein the conductor film is nonuniform in width.
According to a twelfth aspect of the present invention, there is provided the toroidal printed coil manufacturing method according to any one of the first to eleventh aspects, wherein the individual annular juts are cut off from the insulating substrate, whereby the plurality of toroidal printed coils are obtained.
According to a thirteenth aspect of the present invention, there is provided a toroidal printed coil manufactured by the toroidal printed coil manufacturing method according to any one of the first to twelfth aspects.
According to a fourteenth aspect of the present invention, there is provided the toroidal printed coil manufacturing method according to the third aspect, wherein the process for patterning the plating resist layer comprises using a photo-curable photoresist film to form the plating resist layer, and exposing to light one surface of the annular portion on which a ninth mask and a light control sheet are stacked. The ninth mask behaves so as to inhibit light transmission at front-surface pattern forming portions where a conductor film of a front surface of the annular portion is to be formed with the annular portion taken as an axis, to inhibit light transmission at side-portion pattern forming portions where conductor films of outer-and-inner side surfaces of the annular portion are to be formed with the annular portion taken as an axis, and to permit light transmission at the other portions. The light control sheet behaves so as to make incident light scattered or refracted and given off from a side opposite to the incident side. The other surface of the annular portion on which a tenth mask and a light control sheet are stacked are also exposed to light. The tenth mask behaves so as to inhibit light transmission at rear-surface pattern forming portions where a conductor film of a rear surface of the annular portion is to be formed with the annular portion taken as an axis, to inhibit light transmission at side-portion pattern forming portions where conductor films of outer-and-inner side surfaces of the annular portion are to be formed with the annular portion taken as an axis, and to permit light transmission at the other portions. The light control sheet behaves so as to make incident light scattered or refracted and given off from a side opposite to the incident side, thus allowing only the exposed portions of the photoresist film to be cured. Thereafter, the photoresist film is developed to thereby remove uncured portions other than the cured portions, so that the plating resist layer is formed at each of the portions other than the portions where the conductor film of the front surface of the annular portion with the annular portion taken as an axis, the conductor film of the rear surface of the annular portion with the annular portion taken as an axis, and the conductor films of the outer-and-inner side surfaces of the annular portion with the annular portion taken as an axis are to be formed.
According to a fifteenth aspect of the present invention, there is provided the toroidal printed coil manufacturing method according to the third aspect, wherein the process for patterning the plating resist layer comprises using a photo-degradable photoresist film to form the plating resist layer, and exposing to light one surface of the annular portion on which an eleventh mask and a light control sheet are stacked. The eleventh mask behaves so as to permit light transmission at front-surface pattern forming portions where a conductor film of a front surface of the annular portion is to be formed with the annular portion taken as an axis, to permit light transmission at side-portion pattern forming portions where conductor films of outer-and-inner side surfaces of the annular portion are to be formed with the annular portion taken as an axis, and to inhibit light transmission at the other portions. The light control sheet behaves so as to make incident light scattered or refracted and given off from a side opposite to the incident side. The other surface of the annular portion on which a twelfth mask and a light control sheet are stacked are also exposed to light. The twelfth mask behaves so as to permit light transmission at rear-surface pattern forming portions where a conductor film of a rear surface of the annular portion is to be formed with the annular portion taken as an axis, to permit light transmission at side-portion pattern forming portions where conductor films of outer-and-inner side surfaces of the annular portion are to be formed with the annular portion taken as an axis, and to inhibit light transmission at the other portions. The light control sheet behaves so as to make incident light scattered or refracted and given off from a side opposite to the incident side, thus allowing only the exposed portions of the photoresist film to be photo-degraded. Thereafter, the photoresist film is developed to thereby remove only the photo-degraded portions, so that the plating resist layer is formed at each of portions other than the portions where the conductor film of the front surface of the annular portion with respect to the annular axis of the annular portion, the conductor film of the rear surface of the annular portion with respect to the annular axis of the annular portion, and the conductor films of the outer-and-inner side surfaces of the annular portion with respect to the annular axis of the annular portion are to be formed.
According to a sixteenth aspect of the present invention, there is provided the toroidal printed coil manufacturing method according to the third aspect, wherein the process for patterning the plating resist layer comprises using a photo-curable photoresist film to form the plating resist layer, and exposing to light one surface of the annular portion on which a thirteenth mask and a light control sheet are stacked. The thirteenth mask behaves so as to inhibit light transmission at front-surface pattern forming portions where either one of a conductor film of a front surface of the annular portion with the annular portion taken as an axis or a conductor film of a rear surface of the annular portion with the annular portion taken as an axis is to be formed, to inhibit light transmission at side-portion pattern forming portions where conductor films of outer-and-inner side surfaces of the annular portion are to be formed with the annular portion taken as an axis, and to permit light transmission at the other portions. The light control sheet behaves so as to make incident light scattered or refracted and given off from a side opposite to the incident side. The other surface of the annular portion on which a fourteenth mask and a light control sheet are stacked are also exposed to light. The fourteenth mask behaves so as to inhibit light transmission at rear-surface pattern forming portions where either the other one of the conductor film of the front surface of the annular portion with the annular portion taken as an axis or the conductor film of the rear surface of the annular portion with the annular portion taken as an axis is to be formed, to inhibit light transmission at a portion which is to be laid on the annular hole or center hole, and to permit light transmission at the other portions, thus allowing only the exposed portions of the photoresist film to be cured. Thereafter, the photoresist film is developed to thereby remove uncured portions other than the cured portions, so that the plating resist layer is formed at each of portions other than the portions where the conductor film of the front surface of the annular portion with the annular portion taken as an axis, the conductor film of the rear surface of the annular portion with the annular portion taken as an axis, and the conductor films of the outer-and-inner side surfaces of the annular portion with the annular portion taken as an axis are to be formed.
According to a seventeenth aspect of the present invention, there is provided the toroidal printed coil manufacturing method according to the third aspect, wherein the process for patterning the plating resist layer comprises using a photo-degradable photoresist film to form the plating resist layer, and exposing to light one surface of the annular portion on which a fifteenth mask and a light control sheet are stacked. The fifteenth mask behaves so as to permit light transmission at front-surface pattern forming portions where either one of a conductor film of a front surface of the annular portion with the annular portion taken as an axis or a conductor film of a rear surface of the annular portion with the annular portion taken as an axis is to be formed, to permit light transmission at side-portion pattern forming portions where a conductor film of an outer side surface or inner side surface of the annular portion is to be formed with the annular portion taken as an axis, and to inhibit light transmission at the other portions. The light control sheet behaving so as to make incident light scattered or refracted and given off from a side opposite to the incident side. The other surface of the annular portion on which a sixteenth mask and a light control sheet are stacked are also exposed to light. The sixteenth mask behaves so as to permit light transmission only at pattern forming portions where either the other one of the conductor film of the front surface of the annular portion with the annular portion taken as an axis or the conductor film of the rear surface of the annular portion with the annular portion taken as an axis is to be formed, and to inhibit light transmission at the other portions, thus allowing only the exposed portions of the photoresist film to be photo-degraded. Thereafter, the photoresist film is developed to thereby remove only the photo-degraded portions, so that the plating resist layer is formed at each of portions other than the portions where the conductor film of the front surface of the annular portion with the annular portion taken as an axis, the conductor film of the rear surface of the annular portion with the annular portion taken as an axis, and the conductor film of the outer side surface or inner side surface of the annular portion with the annular portion taken as an axis are to be formed.
According to an eighteenth aspect of the present invention, there is provided the toroidal printed coil manufacturing method according to the fifth aspect, wherein the process for patterning the etching resist layer comprises using a photo-curable photoresist film to form the etching resist layer, and exposing to light one surface of the annular portion on which a first mask and a light control sheet are stacked. The first mask behaves so as to permit light transmission at front-surface pattern forming portions where a conductor film of a front surface of the annular portion is to be formed with the annular portion taken as an axis, to permit light transmission at side-portion pattern forming portions where a conductor film of an outer side surface or inner side surface of the annular portion is to be formed with the annular portion taken as an axis, and to inhibit light transmission at the other portions. The light control sheet behaves so as to make incident light scattered or refracted and given off from a side opposite to the incident side. The other surface of the annular portion on which a second mask and a light control sheet are stacked is also exposed to light. The second mask behaves so as to permit light transmission at rear-surface pattern forming portions where a conductor film of a rear surface of the annular portion is to be formed with the annular portion taken as an axis, to permit light transmission at side-portion pattern forming portions where a conductor film of an outer side surface or inner side surface of the annular portion is to be formed with the annular portion taken as an axis, and to inhibit light transmission at the other portions. The light control sheet behaves so as to make incident light scattered or refracted and given off from a side opposite to the incident side, thus allowing only the exposed portions of the photoresist film to be cured. Thereafter, the photoresist film is developed to thereby remove uncured portions other than the cured portions, so that the etching resist layer is formed at each of portions where the conductor film of the front surface of the annular portion with the annular portion taken as an axis, the conductor film of the rear surface of the annular portion with the annular portion taken as an axis, and the conductor film of the outer side surface or inner side surface of the annular portion with the annular portion taken as an axis are to be formed.
According to a nineteenth aspect of the present invention, there is provided the toroidal printed coil manufacturing method according to the fifth aspect, wherein the process for patterning the etching resist layer comprises using of a photo-degradable photoresist film to form the etching resist layer, and exposing to light one surface of the annular portion on which a third mask and a light control sheet are stacked. The third mask behaves so as to inhibit light transmission at front-surface pattern forming portions where a conductor film of a front surface of the annular portion is to be formed with the annular portion taken as an axis, to inhibit light transmission at side-portion pattern forming portions where a conductor film of an outer side surface or inner side surface of the annular portion is to be formed with the annular portion taken as an axis, and to permit light transmission at the other portions. The light control sheet behaves so as to make incident light scattered or refracted and given off from a side opposite to the incident side. The other surface of the annular portion on which a fourth mask and a light control sheet are stacked is also exposed to light. The fourth mask behaves so as to inhibit light transmission at rear-surface pattern forming portions where a conductor film of a rear surface of the annular portion is to be formed with the annular portion taken as an axis, to inhibit light transmission at side-portion pattern forming portions where a conductor film of an outer side surface or inner side surface of the annular portion is to be formed with the annular portion taken as an axis, and to permit light transmission at the other portions. The light control sheet behaves so as to make incident light scattered or refracted and given off from a side opposite to the incident side, thus allowing only the exposed portions of the photoresist film to be photo-degraded. Thereafter, the photoresist film is developed to thereby remove only the photo-degraded portions, so that the etching resist layer is formed at each of portions where the conductor film of the front surface of the annular portion with the annular portion taken as an axis, the conductor film of the rear surface of the annular portion with the annular portion taken as an axis, and the conductor film of the outer side surface or inner side surface of the annular portion with the annular portion taken as an axis are to be formed.
According to a twentieth aspect of the present invention, there is provided the toroidal printed coil manufacturing method according to the fifth aspect, wherein the process for patterning the etching resist layer comprises using, a photo-curable photoresist film to form the etching resist layer, and exposing to light one surface of the annular portion on which a fifth mask and a light control sheet are stacked. The fifth mask behaves so as to permit light transmission at front-surface pattern forming portions where either one of a conductor film of a front surface of the annular portion with the annular portion taken as an axis or a conductor film of a rear surface of the annular portion with the annular portion taken as an axis is to be formed, to permit light transmission at side-portion pattern forming portions where a conductor film of an outer side surface or inner side surface of the annular portion is to be formed with the annular portion taken as an axis, and to inhibit light transmission at the other portions. The light control sheet behaves so as to make incident light scattered or refracted and given off from a side opposite to the incident side. The other surface of the annular portion on which a sixth mask is stacked is also exposed to light. The sixth mask behaves so as to permit light transmission at rear-surface pattern forming portions where either the other one of the conductor film of the front surface of the annular portion with the annular portion taken as an axis or the conductor film of the rear surface of the annular portion with the annular portion taken as an axis is to be formed, and to inhibit light transmission at the other portions, thus allowing only the exposed portions of the photoresist film to be cured. Thereafter, the photoresist film is developed to thereby remove uncured portions other than the cured portions, so that the etching resist layer is formed at each of portions where the conductor film of the front surface of the annular portion with the annular portion taken as an axis, the conductor film of the rear surface of the annular portion with the annular portion taken as an axis, and the conductor film of the outer side surface or inner side surface of the annular portion with the annular portion taken as an axis are to be formed.
According to a twenty-first aspect of the present invention, there is provided the toroidal printed coil manufacturing method according to the fifth aspect, wherein the process for patterning the etching resist layer comprises using a photo-degradable photoresist film to form the etching resist layer, and exposing to light one surface of the annular portion on which a seventh mask and a light control sheet are stacked. The seventh mask behaves so as to inhibit light transmission at front-surface pattern forming portions where either one of a conductor film of a front surface of the annular portion with the annular portion taken as an axis or a conductor film of a rear surface of the annular portion with the annular portion taken as an axis is to be formed, to inhibit light transmission at side-portion pattern forming portions where a conductor film of an outer side surface or inner side surface of the annular portion is to be formed with the annular portion taken as an axis, and to permit light transmission at the other portions. The light control sheet behaves so as to make incident light scattered or refracted and given off from a side opposite to the incident side. The other surface of the annular portion on which an eighth masks stacked is also exposed to light. The eighth mask behaves so as to inhibit light transmission at lead pattern forming portions where either the other one of the conductor film of the front surface of the annular portion with the annular portion taken as an axis or the conductor film of the rear surface of the annular portion with the annular portion taken as an axis is to be formed, to inhibit light transmission at a portion which is to be laid on a through hole, and to permit light transmission at the other portions, thus allowing only the exposed portions of the photoresist file to be photo-degraded. Thereafter, the photoresist film is developed to thereby remove only the photo-degraded portions, so that the etching resist layer is formed at each of portions where the conductor film of the front surface of the annular portion with the annular portion taken as an axis, the conductor film of the rear surface of the annular portion with the annular portion taken as an axis, and the conductor film of the outer side surface or inner side surface of the annular portion with the annular portion taken as an axis are to be formed.